Another thing considered in the luxury market is social class and status. Considering their high prices, even thought the product are of guaranteed quality, it's not for those below avarage to patronise. I have seen cases where people decided to go for low-grade products which they can conveniently afford than save a whole lot for higher grades.
Luxury products are indeed for those who are wealthy and have a higher social class or status. The point is the wealth and affluent also want to distinguish themselves from the masses and prefer using products that are scarce and too expensive for the average people. Luxury products is not only demanded for their durability and quality, but for the self esteem of users.